From what we know though, Tussel has ‘It’s over 9000!’ levels of paradox juice, while Sera’s presumably faded years ago (what with the nightmarish experiments to suck it out of helpless passersby). It seems like, if anything, Sera would be at risk, and not Tussel?

Once it’s extracted, with the right equipment you can open up a portal. At which point anyone could go through. Sera, Corvus, a chair. Although you wouldn’t want to send in that chair, it’s a pretty good chair.